Ornamental · Rosaceae
Great Burnet
Sanguisorba officinalis
Tall wands of dark red bottlebrush flowers that sway over the back of a damp, sunny border all summer.
Full sun
Every 3–7 days
USDA 4–8
2–3 ft · 0.8–0.9 m
Overview
Great burnet draws the eye upward. From a mound of ferny foliage rise slender, wiry stems, and each one is tipped with a tight bottlebrush flower head in a deep red so dark it reads almost black-purple in some lights. The heads cluster along the upper stems, bobbing on the airy growth whenever a breeze moves through the border.
Up close, the contrast is what stands out: the fine, divided leaflets sit low and green near the crown, while the dark red spikes float well above them on stems thin enough to sway. The clump reaches 2.5 to 3 feet (76 to 91 cm) tall and spreads 2 to 3 feet (61 to 91 cm) across, building into a loose, see-through column of color rather than a solid block.
It is an easy perennial that wants the same things season after season: full sun, soil that stays evenly moist, and room for those slender stems to lean and rise. Left to its own devices it scatters seed and sends up volunteers, which tells you how content it is in the right damp, sunny spot.
Care
The short version: Great burnet is an easy, cold-hardy perennial for full sun and steadily moist, well-drained soil. Feed lightly in spring, keep the root zone from drying out, and stake the taller flower stems so the dark red heads stay upright. Cut spent stems to curb self-seeding and shear the whole plant to the ground in late fall or early spring.
Light
Give it full sun for the sturdiest stems and the heaviest show of dark red flower heads. It will take partial shade, but too little light leaves the wiry stems weak, leggy, and prone to leaning under the weight of the bloom.
Water
Keep the soil consistently moist and never let the root zone dry out, especially in summer heat. This is a plant that is happy sitting in damp ground and tolerates moist sites well, so check the soil every few days and water before it dries when rain falls short.
Soil
Average, medium-moisture, well-drained soil suits it, and there is no need to chase a particular pH. Work compost into thin or poor ground, but steer clear of overly rich soil, which pushes soft, floppy stems that cannot hold their flower heads up.
Temperature
This is a tough, cold-hardy perennial for zones 4 through 8. It rides out winters down to about -29°F (-34°C) and shrugs off summer heat up to roughly 86°F (30°C), so no special protection is needed at either end.
Humidity
Ordinary outdoor humidity is fine and there is no figure to aim for. What the plant really cares about is steady soil moisture; when the roots run dry, the ferny leaf edges brown and crisp long before the air ever bothers it.
Feeding
Feed lightly once a season in spring, using a balanced general-purpose fertilizer or a topdressing of compost. On average soil that is plenty, and a heavier hand only produces weak, leggy growth that flops.
Pruning
Trim back the spent flower stems to hold down self-seeding, then cut the whole plant to the ground in late fall or early spring. Stake the taller stems early in the season so they do not sprawl once rain or wind hits them.
Repotting
As a garden perennial it is rarely lifted, and it grows best left in place to build into a clump. Divide it only when crowding starts to thin the flowering or the center of the clump begins to die out.
Size & spacing
Expect a clump 2.5 to 3 feet (76 to 91 cm) tall with a spread of 2 to 3 feet (61 to 91 cm). Give each plant that much room so its airy, slender stems have space to rise and sway.
When to plant
Start seed indoors from late winter into early spring, then move young plants out after the last frost has passed. The dark red flower spikes open in May and run into early summer, with some forms carrying their color later still.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Late winter to early spring
- Plant: Spring after last frost
- Harvest: May to June (into late summer for some forms)
Hardiness
USDA hardiness zones: 4–8
Temperature: down to -34°C
Troubleshooting
This is a clean grower that stays clear of serious pests and disease. The few problems that crop up trace back to where it sits and how wet its roots stay. Catch the early signs and a quick fix keeps the planting sharp.
Crisp brown rims creeping along the ferny leaflets
The fine, ferny foliage turns crisp and brown at the margins and tips when the roots go thirsty. It is the first visible sign that the soil has dried past what this moisture-loving plant likes, and it sharpens during hot, dry stretches.
Fix:
- Water to keep soil evenly moist
- Apply mulch to conserve soil moisture
When the flower wands lean and sag toward the ground
Those slender flowering stems carry their dark red bottlebrush heads high, and the weight up top can pull the whole stem into a lean or sprawl. Soil that is too rich or a spot with too much shade makes the growth soft and stretched, so it bends all the more.
Fix:
- Install stakes or grow-through supports early in the season
- Site in full sun for sturdier stems
Little newcomers springing up beside the parent clump
Once the dark red spikes finish and set seed, the plant scatters it freely, and small volunteer seedlings come up in the ground around the original crown. The parent itself stays fine; you simply get more of it than you asked for.
Fix:
- Deadhead spent flowers before seed sets
- Remove volunteer seedlings by hand
Toxicity
Great burnet is not toxic. It sits among the culinary burnets, and its close relative salad burnet has been cleared as non-toxic to cats, dogs, and horses. A stray nibble from a curious pet is nothing to lose sleep over.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
A cat that bats at or chews the ferny foliage faces no reported toxic reaction from this burnet.
Dogs None
A dog mouthing the leaves or wiry stems should show no poisoning, as the genus carries no reported toxicity.
Horses None
Grazing horses meet no toxic compound here; the related salad burnet is cleared as non-toxic to them.
Rabbits Safe
A rabbit nibbling the soft foliage is fine, with nothing harmful reported in this plant.
Livestock Safe
Cattle, sheep, and other stock can browse the leaves without any reported ill effect.
Birds Safe
Birds picking at the seed heads or foliage encounter no toxic substance.
People Safe
This is a culinary burnet, so a leaf in the mouth poses no toxic worry for people.
No special handling precautions are required; the plant is not reported to be toxic.
Varieties
A couple of named selections deliver the same dark red flowers in either a neater or a taller package. Both are worth seeking out if you want a particular size.
Tanna
A compact selection holding to roughly 12 inches (30 cm), with deep maroon-red bottlebrush heads carried on tidy upright stems.
Red Thunder
A taller, heavily branching form whose deep burgundy-red flowers open from midsummer and carry on into late summer.
How to propagate
Great burnet is easy to multiply. Split an established clump for quick results, or simply let the plant sow itself.
DivisionEasy
Spring or early fall · One growing season
Lift the whole crown of an established clump in spring or early fall, then cut it into sections that each keep healthy roots. Replant the pieces into prepared, moisture-retentive soil, and each one settles in over a single growing season.
SeedEasy
Spring · One to two seasons to flowering size
This plant sows itself freely, so raising it from seed is easy. Sow collected or bought seed in spring into average soil and it comes up readily; the young plants take one to two seasons to reach flowering size.
Myths
Great burnet and the salad burnet you cook with are one and the same plant.
They share a genus and a common name, yet they are different plants. Great burnet is the taller ornamental perennial grown for its dark red flower spikes, while salad burnet, Sanguisorba minor, is the smaller cucumber-flavored kitchen herb. Check the species name before planting if flavor is what you are after.